Ch. 13 - Cognitive Functions

What is lateralization?

The split in function between the left and right hemispheres of the brain.

Is the brain symmetrical like most of nature?

No, the brain is not symmetrical.

What do the left and right hemispheres control?

Each hemisphere controls the opposite side of the body.

Do both hemispheres have the same jobs?

No, each hemisphere has different functions.

How do the brain’s hemispheres share information?

Through the corpus callosum, anterior commissure, hippocampal commissure, and a few smaller commissures.

Which hemisphere is mainly responsible for language?

The left hemisphere (95% of right-handers, 80% of left-handers).

Is the right hemisphere’s function easy to summarize?

No, the right hemisphere’s roles are more complex and harder to summarize.

What is the planum temporale and how does it differ between hemispheres?

A region of the temporal cortex that is larger on the left side in about 65% of people.

When do children shift from right-hemisphere to left-hemisphere dominance for speech?

Young children rely more on the right hemisphere, but the left becomes dominant as they grow.

Do other primates show left–right brain differences like humans?

Yes, similar lateralization and hand preferences appear in chimpanzees, bonobos, and gorillas.

What happens when the corpus callosum is damaged?

Information exchange between the hemispheres is blocked.

What is epilepsy?

A condition involving repeated excessive brain activity, affecting 1–2% of people.

How is epilepsy usually treated?

Most patients respond to medication.

What is a seizure focus?

The specific brain area where seizures originate.

When do doctors cut the corpus callosum?

When seizures can’t be controlled and the focus can’t be removed (e.g., multiple areas or language areas).

What does cutting the corpus callosum accomplish?

It keeps seizures in one hemisphere and often reduces their frequency and duration.

Why do seizures normally last longer without this surgery?

They bounce back and forth between hemispheres, prolonging the activity.

Do split-brain patients lose intelligence or motivation?

No, they remain intellectually normal.

What unusual behavior may split-brain patients show?

Their hands can act independently from each other.

What did Sperry (1974) find about split-brain patients?

They show different responses depending on which visual field the stimulus is shown to.

Why can’t split-brain patients name objects seen in the left visual field?

Because the left visual field goes to the right hemisphere, and the left hemisphere (the language side) can’t access the info.

Can any information still pass between hemispheres after the corpus callosum is cut?

Yes, a small amount can still transfer through minor commissures.

What happens between the hemispheres right after split-brain surgery?

They may initially conflict with each other.

Why does the conflict between hemispheres decrease over time?

Smaller remaining connections help the hemispheres cooperate.

How can hemispheres still show different “opinions”?

They may give different responses depending on which visual field sees a self-portrait or stimulus.

What did Gazzaniga (2000) propose about the left hemisphere?

It acts as an “interpreter,” creating explanations for actions—even when the cause is unconscious.

Which hemisphere is essential for speech?

The left hemisphere.

What is the right hemisphere especially good at?

Spatial relationships, seeing the big picture, and understanding context.

What happens if the right hemisphere is damaged?

Difficulty perceiving emotions, humor, and sarcasm; speech may become monotone.

What happens when the left hemisphere is inactivated?

The person cannot speak.

What happens when the right hemisphere is inactivated?

The person can describe emotional events but does not feel the emotion.

How do we learn most of what we know about language in the brain?

By studying people with brain damage.

What happens when Broca’s area is damaged?

It causes language impairments.

What is aphasia?

A language disorder.

What is Broca’s aphasia?

A condition where a person has trouble producing language.

Does damage to Broca’s area alone always cause severe aphasia?

No, damage limited to Broca’s area typically causes only mild problems.

Why can people sometimes still speak after Broca’s area is damaged?

Speaking involves many brain areas, which can adapt and compensate.

What is the main symptom of Broca’s aphasia?

low, awkward language production.

Does Broca’s aphasia affect both speech and sign language?

Yes, it affects all forms of language production.

What types of words are often omitted in Broca’s aphasia?

Grammatical words like pronouns, prepositions, and helping verbs.

Why do patients omit these words?

Because producing speech is difficult, so they focus on essential content words.

Where is Wernicke’s area located?

Near the auditory cortex.

What is Wernicke’s aphasia (fluent aphasia)?

A condition with fluent, smooth speech but poor language comprehension and difficulty finding words.

Is object recognition usually affected in Wernicke’s aphasia?

No, it is usually intact.

What is anomia?

Trouble recalling the names of objects.

How does speech sound in Wernicke’s aphasia?

Fluent and articulate, but with pauses to search for words.

What aspects of language comprehension are impaired?

Understanding speech, writing, and sign language.

How is second-language comprehension controlled in bilingual people?

It varies—some rely mainly on the left hemisphere, some on the right, and others use both equally.

Who shows the most variable hemispheric control for language?

People fluent in two or more languages, especially those bilingual since infancy.

What strongly affects language-learning ability?

Individual differences.

What is dyslexia?

Difficulty reading despite normal vision, motivation, and intelligence.

Who is dyslexia more common in?

Boys.

Is dyslexia genetic?

Yes, it is highly heritable, but no single major gene causes it.

Does dyslexia occur only in certain languages?

No, it is found in all languages.

What is a core difficulty in dyslexia?

Converting written words into their sounds.

What brain differences are often seen in dyslexia?

Abnormalities in the left hemisphere.

How does the visual word form area behave in dyslexia?

It responds less to written words and more to other objects.

What additional problems may some people with dyslexia have?

Poor auditory memory or impaired eye movements.

Do all cases of dyslexia have the same cause?

No, reading difficulties vary and no single explanation fits all cases.

What sound-processing issue may contribute to dyslexia?

Difficulty processing the order of sounds (a brain processing problem, not a hearing problem).

Are attention differences common in dyslexia?

Yes, attention alterations are frequently seen.

How might visual perception differ in dyslexia?

Individuals may recognize letters better slightly to the right of where they are directly looking.

What does difficulty with the temporal order of sounds suggest in dyslexia?

A problem with how the brain processes auditory information, not with hearing itself.

What kind of attention differences are common in dyslexia?

Alterations in attention.

How can visual recognition be shifted in dyslexia?

Individuals may identify letters more easily slightly to the right of their fixation point.

What is consciousness?

The relationship between the mind and the brain.

What is dualism?

The view that the mind and body are different substances.

What did Descartes propose about mind–brain interaction?

That the mind and brain interact at a single point, possibly the pineal gland.

Do most modern philosophers and neuroscientists support dualism?

No, nearly all reject it.

Why does dualism conflict with physics?

A mind not made of matter or energy could not cause anything to happen, including muscle movements.

What is monism?

The view that the universe is one substance.

What are the three main types of monism?

Materialism (everything is physical)

Mentalism (only the mind exists)

Identity position (mental processes are the same as certain brain processes).

Why is consciousness difficult to study?

It is hard to define and cannot be directly observed.

What can brain mapping reveal about consciousness?

It shows why stimuli differ in brain activity (e.g., why a lemon smells different from an orange) but not the subjective experience itself.

What is an operational definition of consciousness?

If a person reports noticing one stimulus but not another, they are conscious of the first stimulus only.

What is an example test of consciousness?

Flash suppression, where a stationary dot can become invisible when other dots flash around it.

What is binocular rivalry?

Slow shifts in perception when each eye sees a different image.

What does fMRI show during binocular rivalry?

Switching between images changes brain activity patterns across large areas.

What happens if the images shown to each eye are very similar?

The brain fuses them into a single perception.

What must happen for a stimulus to enter consciousness?

The brain must recognize it as meaningful.

Can unconscious brain activity influence behavior?

Yes, much brain activity is unconscious but can still affect behavior.

Which brain area is most associated with consciousness?

The cerebral cortex.

What does consciousness require in terms of brain function?

Integration of information.

How does the cerebral cortex support information integration?

Through long-range reciprocal connections that let each area influence many others and receive feedback.

What do these cortical connections enable?

Information to spread, compare, and interact across the brain.

Is there a delay between an event and our conscious awareness of it?

Yes, delays exist between an event and our consciousness of it.

What is the phi phenomenon?

When a dot in one position alternates with a nearby dot, it appears to move back and forth.

How does the second dot affect perception?

It changes how we perceive what occurred at the first position.

What is one main question about the physiology of consciousness?

How does an alert person become aware of a specific stimulus?

What allows a person or animal to be conscious in general?

What happens to brain activity under anesthesia?

Overall brain activity decreases, dopamine levels drop, and cortex-thalamus connectivity is reduced.

What happens during recovery from anesthesia?

Connectivity is restored first, followed by an increase in cortical activity.

How can fMRI reveal consciousness in vegetative patients?

Imagining tasks like playing tennis activates the motor cortex, and some can answer yes/no questions this way.

What is another method to infer consciousness?

Magnetic stimulation of a brain area with EEG to record how activity spreads.

Is consciousness unique to humans?

No, pets and some other animals likely experience it.

Can some invertebrates have conscious experiences?

Yes, they may feel pain, suggesting consciousness.

How do monkeys help study consciousness?

They show the same distinction between conscious and unconscious stimuli as humans, allowing empirical study.

How is attention related to consciousness?

Attention is closely linked to consciousness.

What is inattentional or change blindness?

Slow or unnoticed changes in a scene go unnoticed unless focused on.

What are the two types of attention?

Bottom-up (automatic reaction)

Top-down (intentional focus).

What is an example of bottom-up attention?

Automatically noticing a deer in the forest.